8721936785 has 16 divisors (see below), whose sum is σ = 11291090256. Its totient is φ = 6443194368.

The previous prime is 8721936763. The next prime is 8721936793. The reversal of 8721936785 is 5876391278.

It can be written as a sum of positive squares in 8 ways, for example, as 260144641 + 8461792144 = 16129^2 + 91988^2 .

It is a cyclic number.

It is not a de Polignac number, because 8721936785 - 2¹⁸ = 8721674641 is a prime.

It is a super-2 number, since 2×8721936785² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8721936785.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 963524 + ... + 972533.

It is an arithmetic number, because the mean of its divisors is an integer number (705693141).

Almost surely, 2^8721936785 is an apocalyptic number.

8721936785 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

8721936785 is a deficient number, since it is larger than the sum of its proper divisors (2569153471).

8721936785 is a wasteful number, since it uses less digits than its factorization.

8721936785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936132.

The product of its digits is 5080320, while the sum is 56.

The square root of 8721936785 is about 93391.3100079445. The cubic root of 8721936785 is about 2058.4373093005.

The spelling of 8721936785 in words is "eight billion, seven hundred twenty-one million, nine hundred thirty-six thousand, seven hundred eighty-five".